* {
    margin: 0;
    padding: 0;
}

header {
    display: block;
    margin: 0 auto;
    width: 100%;
    height: auto;
    text-align: center;
}

header h1 {
    margin: 20px auto 0;
    font-family: Arial;
    font-size: 60px;
    font-weight: bold;
}

header #newgamebutton {
    display: block;
    width: 30%;
    height: 20px;
    margin: 20px auto 0;
    padding: 10px 6px;
    font-weight: bold;
    line-height: 20px;
    background-color: #8f7a66;
    font-family: Arial;
    color: white;
    border-radius: 10px;
    text-decoration: none;
}

header #newgamebutton:hover {
    background-color: #9f8b77;
}

header p {
    font-family: Arial;
    font-style: 25px;
    margin: 20px auto;
}

@media (min-width: 300px) {
    header #newgamebutton {
        width: 25%;
        margin: 10px auto 0;
    }
    header p {
        margin: 10px auto 0;
        font-size: 26px;
    }
}

@media (min-width: 400px) {
    header #newgamebutton {
        width: 25%;
    }
}

@media (min-width: 500px) {
    header {
        width: 500px;
    }
    header #newgamebutton {
        width: 100px;
        margin: 20px auto 0;
    }
    header p {
        margin: 20px auto 0;
        font-size: 30px;
    }
}

#grid-container {
    width: 460px;
    height: 460px;
    padding: 20px;
    margin: 50px auto;
    background-color: #bbada0;
    border-radius: 10px;
    position: relative;
}

.grid-cell {
    width: 100px;
    height: 100px;
    border-radius: 10px;
    background-color: #ccc0b3;
    position: absolute;
}

.number-cell {
    border-radius: 6px;
    font-family: Arial;
    font-weight: bold;
    font-size: 60px;
    line-height: 100px;
    text-align: center;
    position: absolute;
}

.block {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    line-height: 150px;
    font-family: Arial, Helvetica, sans-serif;
    font-size: 50px;
    font-weight: bold;
    border-radius: 20px;
}